Injury Severity Scoring Flashcards

Which statement about the Organ Injury Scale (OIS) and AIS is correct?

Answer: OIS grades (I–V) generally correspond to AIS severity levels for specific organs

The AAST Organ Injury Scale grades (I–V) broadly parallel AIS severity codes and are often cross-referenced in operative trauma.

A trauma patient has an ISS of 25. What is the approximate 30-day mortality rate in a typical US Level I trauma center?

Answer: Approximately 10–20%

An ISS of 25 corresponds to roughly 10–20% mortality depending on age, mechanism, and center performance.

Which component is NOT part of the Revised Trauma Score (RTS)?

Answer: Injury Severity Score

The RTS uses only GCS, systolic blood pressure, and respiratory rate; ISS is an anatomic score not included in RTS.

When coding a closed head injury, the AIS body region assigned is:

Answer: Head/Neck

All brain and spinal cord injuries, skull fractures, and cervical injuries are coded under the Head/Neck region.

For quality improvement benchmarking, W-statistics derived from TRISS represent:

Answer: The number of unexpected deaths per 100 patients

The W-statistic estimates the number of survivors or non-survivors per 100 patients beyond what TRISS-predicted probability would expect.

An AIS severity of 4 is described as:

Answer: Severe

AIS 4 is designated 'severe' on the six-point scale: minor(1), moderate(2), serious(3), severe(4), critical(5), unsurvivable(6).

Which factor most directly determines why ISS is squared rather than simply summed?

Answer: To weight more severe individual injuries more heavily in the aggregate score

Squaring AIS values exponentially increases the contribution of higher-severity injuries, reflecting their disproportionate effect on mortality.